IgG avidity assay firms up the diagnosis of acute toxoplasmosis on the first serum sample in immunocompetent pregnant women

Candolfi, Ermanno; Pastor, Rebecca; Huber, Rachel C.; Filisetti, Denis; Villard, Odile

doi:10.1016/j.diagmicrobio.2006.12.010

Cited by 81 publications

(63 citation statements)

References 27 publications

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“…In clinical situations in which the date of the T. gondii infection is difficult to establish, Toxoplasma IgG avidity testing can be performed (14)(15)(16). Since 2006, the French National Reference Center for Toxoplasmosis (NRCT) has been entrusted with evaluation of the methods used for the serological diagnosis of toxoplasmosis (11,12) in accordance with national recommendations (17).…”

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confidence: 99%

Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis

et al. 2016

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h Toxoplasmosis, a benign infection, is asymptomatic or paucisymptomatic in over 80% of cases, except in immunocompetent patients suffering from ocular toxoplasmosis or in immunocompromised patients with opportunistic or congenital toxoplasmosis. Diagnosis is based mainly on serology testing. Thus, we compared the performance of the nine most commonly used commercial automated or semiautomated immunoassays for IgG and IgM Toxoplasma gondii antibody detection, that is, the Advia Centaur, Architect, AxSYM, Elecsys, Enzygnost, Liaison, Platelia, VIDAS, and VIDIA assays. The assays were conducted on four panels of serum samples derived during routine testing from patients with an interfering disease and who exhibited a low IgG antibody level in one of two clinical settings, namely, acute or chronic toxoplasmosis. As a result, IgG sensitivities ranged from 97.1% to 100%, and IgG specificities ranged from 99.5% to 100%. For IgG quantification, strong differences in IgG titers (expressed in IU/ml) were noted depending on the assay used. IgM sensitivities ranged from 65% to 97.9%, and IgM specificities ranged from 92.6% to 100%. For defining the best serological strategies to be implemented, it appears crucial to compare the diagnostic performance of the different tests with respect to their specificity and sensitivity in detecting the presence of IgG and IgM antibodies.

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confidence: 99%

Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis

et al. 2016

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“…Consequently, serological tests other than those for IgG and IgM detection have been developed to facilitate the diagnosis of seroconversion. The measurement of IgG avidity was developed almost 20 years ago to exclude any infection acquired in the preceding 3 or 4 months using most commercial tests (16,17,18,19,20,21,22,23,24). Immunoblot analysis (Toxo II IgG test; LDBio, Lyon, France) may promptly confirm the seroconversion when IgG concentrations detected with routine tests are negative or equivocal (25,26,27).…”

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Toxoplasma Seroconversion with Negative or Transient Immunoglobulin M in Pregnant Women: Myth or Reality? A French Multicenter Retrospective Study

et al. 2013

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Classically, Toxoplasma infection is associated with high levels of specific IgM antibody and a rise in specific IgG levels 1 to 3 weeks later. Atypical IgG seroconversion, without IgM detection or with transient IgM levels, has been described during serologic follow-up of seronegative pregnant women and raises difficulties in interpreting the results. To evaluate the frequency and the characteristics of these atypical cases of seroconversion, an investigation was conducted within the French National Reference Center for Toxoplasmosis, from which 26 cases collected from 12 laboratories belonging to the network were identified. The aim of this work was to retrospectively analyze the results of serologic testing, the treatments administered, and the results of prenatal and postnatal follow-up for these women. In each case, IgG antibodies were detected using both screening and confirmatory tests. IgM antibodies were not detected in 15 cases, and the levels were equivocal or low-positive in 11 cases. The IgG avidity results were low in 16 cases and high in one case. Most of the pregnant women (22/26) were treated with spiramycin from the time that IgG antibodies appeared until delivery. Amniotic fluid was analyzed for Toxoplasma gondii DNA by PCR in 11/26 cases, and the results were negative in all cases. Congenital toxoplasmosis was ruled out in 12/26 newborns. There was no abnormality observed at birth for 10 newborns and no information available for 4 newborns. In conclusion, when the interpretation of serological results is so difficult, it seems cautious to initiate treatment by spiramycin and to follow the pregnant women and their newborns.

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“…A low IgG avidity index assists in diagnosing acute acquired T. gondii infection and identifying pregnancies that are at a high risk for congenital toxoplasmosis. A study has demonstrated that IgG avidity assay (Platelia) has 100% sensitivity and 92.7% specificity for the detection of acute T. gondii infection (3).…”

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confidence: 99%

Prospective Study of Congenital Toxoplasmosis Screening with Use of IgG Avidity and Multiplex Nested PCR Methods

et al. 2011

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IgG avidity assay firms up the diagnosis of acute toxoplasmosis on the first serum sample in immunocompetent pregnant women

Cited by 81 publications

References 27 publications

Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis

Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis

Toxoplasma Seroconversion with Negative or Transient Immunoglobulin M in Pregnant Women: Myth or Reality? A French Multicenter Retrospective Study

Prospective Study of Congenital Toxoplasmosis Screening with Use of IgG Avidity and Multiplex Nested PCR Methods

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